1. Field of the Invention
The present invention relates to a flat panel display device, and more particularly, to encapsulating a flat panel display device.
2. Discussion of Related Art
Recently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of a cathode ray tube (CRT), have been developed. As the flat panel display device, there are a liquid crystal display, a field emission display, a plasma display panel and a light emitting display, etc. There have widely been studied the flat panel display devices since they can be constituted in super thin and flexible form in terms of driving characteristic. Among others, since the field emission display has the characteristic that is degraded by an infiltration of moisture, it needs a sealing member for preventing the infiltration of moisture.
Generally, there is a method fabricating a sealing member by machining a metal can or a glass substrate in a cap form to have a groove, wherein after a desiccant for absorbing moisture is mounted in the groove in a powder form or fabricated in a film form to be adhered to it using a double-faced tape, the sealing member is bonded to the substrate on which the organic light emitting elements are formed, using UV curing sealant or thermosetting sealant. That is, according to the exemplary method, although the sealing member is bonded to the substrate on which the elements are formed, using the UV curing sealant or the thermosetting sealant, there may be a limitation to prevent the infiltration of oxygen or moisture since the bonding material is sealant.
In case that oxygen or moisture is infiltrated into inside of the elements, it has disadvantages that degradation due to intrinsic factors, such as degradation of an emission layer due to oxygen from a first electrode ITO, degradation due to a reaction of the emission to an interface, etc., as well as degradation due to extrinsic factors, such as moisture, oxygen, ultraviolet rays, and fabrication conditions of the elements, etc., easily occur. That is, it causes problems that due to the infiltration of moisture from the external into the inside of a display unit, the emission layer is separated from an electrode and poor pixels are generated, etc.
The structure sealing the organic light emitting display device by applying the frit on the glass substrate is disclosed in U.S. Pat. No. 6,998,776, wherein it uses the frit and melts it by a laser so that the gap between the substrate for the elements and the cap is sealed.
The discussion in this section is to provide general background information, and does not constitute an admission of prior art.